Why?

Why should men favor the will of women over their own? Because basically most men are entitlement hogs. They were conditioned to be. They were conditioned to think women want them to be.

In female-male relationships men are working with women, a people group that doesn't have the same sense of entitlement to receive as men do because they haven't been encouraged to be the center of attention and support in group situations; and men are dealing with an ego that blinds them to the needs of others so that they tend to assert their wants over others' needs. Unless they change relationship dynamics to build up her confidence and minimize his ego, they will most likely grow farther apart.

How can a man and a woman trust their minds not to play tricks on them as they revert back to her denial and sacrifice of what she wants for his assertion of what he wants? -By a man making active sacrifices of his wants to nurture hers, and his self-importance to demonstrate hers, as an exercise or effort to remind himself of the humility he needs to get in touch with to be fair to her. It is an exercise, both for the man and the woman, to talk differently and act differently than the "norm", if you will, in order to practice this mentality, which is like a ritual that helps one internalize ideas to achieve a mental or character change.

In order to make a woman happy, a man needs to focus on responding to and supporting her will; and this cannot be done while the man is simultaneously focused on what he wants, because he will never focus on his benefit and her benefit equally. He will always favor his benefit unless he makes a conscious effort to favor her interest and benefit.

When a man pushes and pushes for his will in a relationship by giving lip service and then pushing the boundary she has already expressed by making suggestions and taking actions that counter her will, his sense of entitlement wears down a woman until she gives up being confident in her will for herself, or the relationship. She starts to doubt the importance of her will as she sees his confidence and energy competing with hers in all kinds of disagreements. This motivates a woman to leave a man.

And men are easier to please than women. So it is more of an accomplishment for a man to please a woman than it is for him to please himself, and this accomplishment is pleasing in and of itself.

Unless men approach a relationship with a woman by focusing on what they have to offer her, rather than what they want to get, they will not be able to please a woman, and the only way it seems they can enter this state of mind is to actively deny their wants in order to help meet her needs, and her wants.